Stamp collecting is an individual pursuit. I have no doubt that there are a
lot of collectors out there with really big numbers. I personally know collectors that are well into six figures. One has zero online presence, other than buying on
ebay. His shelves of green binders are staggering. Another posts occasionally in the upside-down stamp community, but is otherwise invisible.
Now, you have to allow for postmarks, pages with identified fakes, South American paper varieties, locals, revenues, etc., including write-ups across dozens of catalogues. If we need to measure this by spaces in Blue or Brown albums, that's a different limitation.
I would hope that I could have 40 more years to follow that same path, but any guess of eventual totals is completely speculative. I'm pretty specific in my interests, so the KGV portion of my collection may never hit 50,000, much less 100,000.